Masamitsu Shimazawa,1 Satomi Chikamatsu,1 Nobutaka Morimoto,1,2 Satoshi Mishima,3 Hiroichi Nagai,2 and Hideaki Hara1*
1Department of Biofunctional Molecules, Gifu Pharmaceutical University, Gifu, Japan
2Department of Pharmacology, Gifu Pharmaceutical University, Gifu, Japan
3Research Center, API Co. Ltd, Gifu, Japan
*For reprints and all correspondence: Professor H. Hara, PhD, Department of Biofunctional Molecules, Gifu Pharmaceutical University, 5-6-1 Mitahora-higashi, Gifu, 502-8585 Japan. Tel: +81-58-237-3931; Fax: +81-58-237-5979; E-mail: email@example.com
Received January 4, 2005; Accepted March 6, 2005.
We examined whether Brazilian green propolis, a widely used folk medicine, has a neuroprotective function in vitro and/or in vivo. In vitro, propolis significantly inhibited neurotoxicity induced in neuronally differentiated PC12 cell cultures by either 24 h hydrogen peroxide (H2O2) exposure or 48 h serum deprivation. Regarding the possible underlying mechanism, propolis protected against oxidative stress (lipid peroxidation) in mouse forebrain homogenates and scavenged free radicals [induced by diphenyl-p-picrylhydrazyl (DPPH). In mice in vivo, propolis [30 or 100 mg/kg; intraperitoneally administered four times (at 2 days, 1 day and 60 min before, and at 4 h after induction of focal cerebral ischemia by permanent middle cerebral artery occlusion)] reduced brain infarction at 24 h after the occlusion. Thus, a propolis-induced inhibition of oxidative stress may be partly responsible for its neuroprotective function against in vitro cell death and in vivo focal cerebral ischemia.
Keywords: focal cerebral ischemia, free radical, lipid peroxidation, middle cerebral artery occlusion, PC12 cell culture